Recombinant Human

Apolipoprotein H/ApoH Catalog Number: 5087-AH

DESCRIPTION Source Mouse myeloma cell line, NS0­derived Met1­Cys345 Accession # P02749

N­terminal Sequence Gly20 Analysis Structure / Form Monomer

Predicted Molecular 36.3 kDa Mass

SPECIFICATIONS SDS­PAGE 57­60 kDa, reducing conditions

Activity Measured by its binding ability in a functional ELISA. When recombinant human ApoH is immobilized at 2 μg/mL, 100 µL/well, the concentration of recombinant human LDL R (Catalog # 2148­LD) that produces 50% of the optimal binding response is found to be approximately 0.2 ­ 0.8 μg/mL.

Endotoxin Level <0.01 EU per 1 μg of the protein by the LAL method.

Purity >95%, by SDS­PAGE under reducing conditions and visualized by silver stain. Formulation Lyophilized from a 0.2 μm filtered solution in PBS. See Certificate of Analysis for details.

PREPARATION AND STORAGE Reconstitution Reconstitute at 500 μg/mL in PBS.

Shipping The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below. Stability & Storage Use a manual defrost freezer and avoid repeated freeze­thaw cycles. l 12 months from date of receipt, ­20 to ­70 °C as supplied. l 1 month, 2 to 8 °C under sterile conditions after reconstitution. l 3 months, ­20 to ­70 °C under sterile conditions after reconstitution.

BACKGROUND Apolipoprotein H (ApoH), also known as β2­Glycoprotein I/β2­GPI, is a 50 kDa variably glycosylated member of the complement control superfamily of proteins (1, 2). Mature human ApoH consists of four tandem Sushi/SCR repeats followed by one Sushi­like repeat (3, 4). Mature human ApoH shares 76% and 82% aa sequence identity with mouse and rat ApoH, respectively. Hepatocyte­derived ApoH binds directly to negatively charged phospholipids (5). It circulates as a component of lipoprotein particles and as a lipid­free serum protein (6). ApoH also associates with liposomes and apoptotic cell debris, thereby enabling their renal clearance via Megalin uptake (7, 8). Circulating levels of ApoH are postively correlated with triglyceride­rich lipoprotein (VLDL) components in type II diabetes (9). ApoH inhibits thrombosis by blocking the activation of Coagulation Factor XI but also shows procoagulant activity by inhibiting the activation of Protein C (10, 11). ApoH can be cleaved by Plasmin at Lys317 ­ Thr318, an action that is enhanced by heparin (12, 13). ApoH cleavage reduces its ability to bind phospholipids and inhibit Factor XI activation but confers the ability to bind Plasminogen (10, 12, 14). Cleaved ApoH also demonstrates antiangiogenic activity, whereas intact ApoH does not (14). The production of antibodies against ApoH is a hallmark of Antiphospholipid Syndrome (APS), an autoimmune disorder that leads to hypercoagulability and recurrent miscarriages (15). ApoH binds to the surface antigen of Hepatitis B Virus and is associated with the development of HBV­induced hepatocellular carcinoma (6, 16).

References: 1. Crook, M.A. et al. (2010) Atherosclerosis 209:32. 2. Miyakis, S. et al. (2004) Thromb. Res. 114:335. 3. Steinkasserer, A. et al. (1991) Biochem. J. 277:387. 4. Lozier, J. et al. (1984) Proc. Natl. Acad. Sci. 81:3640. 5. Wurm, H. (1984) Int. J. Biochem. 16:511. 6. Mehdi, H. et al. (1994) J. Virol. 68:2415. 7. Chonn, A. et al. (1995) J. Biol. Chem. 270:25845. 8. Moestrup, S.K. et al. (1998) J. Clin. Invest. 102:902. 9. Castro, A. et al. (2010) Atherosclerosis 209:201. 10. Shi, T. et al. (2004) Proc. Natl. Acad. Sci. 101:3939. 11. Mori, T. et al. (1996) Thromb. Haemost. 75:49. 12. Hunt, J. et al. (1993) Proc. Natl. Acad. Sci. 90:2141. 13. Guerin, J. et al. (2002) J. Biol. Chem. 277:2644. 14. Sakai, T. et al. (2007) Am. J. Pathol. 171:1659. 15. Adams, M. (2008) Semin. Thromb. Haemost. 34:251. 16. Jing, X. et al. (2010) J. Cancer Res. Clin. Oncol. 16:1671.

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